John Stockton

 

New Scientist 6th February 1975. Vol 65 No 935.

6^th February 1975 was something of a watershed moment in Earth Science and its relationship to the public. Not one but two articles in New Scientist that week featured James Lovelock. The first, co-authored by Lovelock with Dr Sidney Epton, outlined the  Gaia hypothesis, and the second written by Martin Sherwood was a profile of “Jim Lovelock” and his wider scientific and technological achievements.

The Quest for Gaia has the useful sub heading “Do the Earth's living matter, air, oceans and land surface form part of a giant system which could be seen as a single organism? Could man's activities reduce such a system's options so that it is no longer able to exert sufficient control to stay stable?”

In 1975 It had been long believed that distinct ecologies had populations of species that were adapted to the geological and climatic conditions of their environment but James Lovelock suggested that this was a two way process, with living organisms collectivily combining micro-forces to effectively engineer the atmosphere and the oceans as well as maintaining them within ranges of temperature and salinity that are favourable to life. The article is careful to refer to the Gaia concept as a hypothesis and not a theory, as no planetary scale experiments are possible, although it could be argued that the increase in atmospheric carbon dioxide levels that we worry about now are a kind of accidental test with unpredictable results.

The Gaia hypothesis remains controversial today. Opinion ranges from enthusiastic comparison with the Copernican revolution in astronomy to dismissal of Gaia as new age mysticism, but for the majority of scientists in the middle James Lovelock's work has given a tremendous impetus to Earth systems science.

Lovelock was clear about the complexity of earth systems and the challenge of understanding their exact functioning. "Gaia is still a hypothesis. The facts and speculations in this article and others that we have assembles corroborate but do not prove her existence but, like all useful theories right or wrong, Gaia suggests new questions which may throw light on old ones.” Lovelock then went on to describe how the oxygen produced by photosynthesis, early in Earth's history, would have been toxic to the majority of living organisms. The availability of oxygen subsequently made possible the evolution of more complex life. From the perspective of 1975, the capacity of humans to create a pollution problem as damaging as the 'great oxidation event' seemed quite trivial by comparison, but Lovelock had a warning for the future. “If one showed a control engineer a graph of the Earth's mean temperature against time over the past million years, he would no doubt remark that it represented the behaviour of a system in which serious instabilities could develop but which had never gone out of control. One of the laws of system control is that if a system is to maintain stability it must possess adequate variety of response, that is, have at least as many ways of countering outside disturbances as there are outside disturbances to act on it.”

In one eloquent paragraph James Lovelock explained that the need to maintain biodiversity was not to meet an aesthetic ideal. The survival of humans depends on the continued functioning of Earth systems which have complexities that we may not understand.

Pages 313 to 315 of issue 935 features Cosmic gamma-ray bursts by Dr Andrew Fabian and Dr James Pringle. “ Transient phenomena are becoming a natural aspect of high-energy astrophysics. In recent months short bursts of gamma rays have been observed from a number of space platforms, leaving theorists perplexed- although not altogether tongue-tied – as to their origin”

In 1975 mysterious bursts of gamma rays lasting about ten seconds emanating from space were mysterious as no known astronomical objects were known to be located at their points of origin. The open question was made more intriguing by the accidental nature of their discovery. The 1963 Partial Test Ban Treaty forbade the atmospheric (surface) testing of Nuclear and thermonuclear weapons, and five Vela satellites were placed in Earth orbit to detect gamma rays from any clandestine explosions. As soon as the satellites registered gamma rays the events would have been taken very seriously.

Although the satellites were launched one week after the implementation of the treaty it was ten years before the detection of the Gamma ray bursts was revealed. “R.W. Klebesadel, I.B. Strong and R.A. Olson of the Los Alamos Scientific Laboratory announced the discovery of the first 16 cosmic gamma-ray bursts in 1973. Since then another eight or so have been reported, as well as other sightings of several bursts by detectors on OGO-3, IMP-6, OSO-7 and the Apollo16. This last system, in the Apollo 16 command module, was designed for determining lunar surface composition by by fluorescence techniques.”

By triangulating from the different arrival times of the gamma ray bursts at different satellites, it was initially determined that they emanated from beyond the solar system and the burst that was detected by satellites as well as the Apollo 16 astronauts orbiting the moon was traced to region away from the plane of the Milky Way and close to the Small Magellanic Cloud. From the perspective of 1975, the mystery surrounding gamma ray bursts was compounded by the lack of data. The success of triangulation from the arrival times of bursts at the positions of different satellites was limited by timing errors, which resulted in the search zones 15 degrees wide. Theories ranged from comets plunging into neutron starts, through star quakes and super flares, to nuclear holocausts resulting from global warfare on alien planets.